Studies On Resistance Of Toona Sinensis To Heavy Metal

The partial crop of subur was polluted by the heavy metals in China, which is harmto human. The Toona sinensis is a high efficiency, multifunctional woody vegetableresources in the nutritional value of food, medicinal health value, economic value andeco-tourism value. The resistance of Toona sinensis to the copper, zinc, mercury,cadmium, lead and chromium was studied by pot, which is very important todevelopment of urban agriculture and improvement of food security.(1) The growth status and tissue water content of Toona sinensis under heavy metalwere studied. The result showed that the germination was delayed (3~23 d). Thegrowth of shoot, crown width, height, diameter, tiller and leaf area was promoted inthe low concentration of copper or zinc, and inhibited in the high concentrations. Butthe growth of Toona sinensis was inhibited in the all concentrations of other fourheavy metals. The fresh weigh water content, relative water, water saturation deficitof the leaf and fresh weigh water content of the petiole were little difference under thesame kind of heavy metal stress.(2) The chlorophyll a, chlorophyll b, chlorophyll a and b content were firstincreased and then decreased with increasing of stress concentration of five heavymetals. The chlorophyll a/b was increased; MDA content was first reduced and thenincreased; CAR content was reduced with increasing of concentration of copper. Thechlorophyll a/b was higher than that of contol group; MDA content was reduced;CAR content was reduced and then increased with increasing of concentration of zinc.The chlorophyll a/b and CAR content were little difference; MDA content wasreduced with increasing of concentration of mercury. The chlorophyll a/b was littledifference; MDA content was higher than that of contol group; CAR content wasreduced with increasing of concentration of cadmium. The MDA content was firstincreased and then reduced; chlorophyll a/b was reduced and then increased; CARcontent was increased with increasing of concentration of lead.(3) The soluble protein and soluble sugar were first reduced and then increasedsignificantly at 0.05 level; content of vitamin C, tartaric acid and malic acid，nutrientelement were increased first and then decreased with increasing of concentration ofcopper. The soluble protein content was first decreased and then increased; content ofsoluble sugar, vitamin C, tartaric acid and malic acid, copper, calcium, iron,magnesium, manganese were first increased and then decreased; content of zinc wasincreased with increasing of concentration of zinc. The content of soluble protein,tartaric acid and malic acid, calcium, iron, magnesium, manganese was first increasedand then decreased; content of soluble sugar was first decreased and then increased;content of vitamin C was decreased with increasing of stress concentration of mercury. The content of soluble protein, vitamin C, iron, magnesium, manganese was firstincreased and then decreased; content of soluble sugar was first decreased and thenincreased; content of calcium was increased; content of tartaric acid and malic acidshowed the trend of the“M”with increasing of stress concentration of cadmium. Thecontent of soluble protein was lower than that of control group; content of solublesugar, tartaric acid and malic acid, vitamin C was first increased and then decreased;content of calcium, iron, magnesium, manganese was increased with increasing ofstress concentration of lead. The content of copper, iron, manganese, zinc was firstdecreased and then increased; content of calcium, magnesium were decreased withincreasing of stress concentration of chromium.(4) The result showed that the leaf of Toona sinensis was low absorption of copper,cadmium and lead, and high absorption of zinc, mercury and chromium. The leaf ofToona sinensis could have strong ability to absorb and accumlate plenty of strontiumand nickel; followed by manganese and chromium; ability to absorb cadmium, leadand barium was weak under six heavy metals stress. The stem of Toona sinensis couldhave strong ability to absorb and accumlate plenty of strontium, lead and nickel;followed by manganese, cadmium and chromium; ability to absorb barium was weak.The root of Toona sinensis could have strong ability to absorb and accumlate plenty ofstrontium, lead and nickel; followed by manganese, cadmium and chromium; abilityto absorb barium was weak. Manganese, barium and nickel were transport easily inthe tissue of Toona sinensis; and followed by strontium and chromium.